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  • Why is cell phone software still so primitive?

    - by Tomislav Nakic-Alfirevic
    I don't do mobile development, but it strikes me as odd that features like this aren't available by default on most phones: full text search: searches all address book contents, messages, anything else being a plus better call management: e.g. a rotating audio call log, meaning you always have the last N calls recorded for your listening pleasure later (your little girl just said her first "da-da" while you were on a business trip, you had a telephone job interview, you received complex instructions to do something etc.) bluetooth remote control (like e.g. anyRemote, but available by default on a bluetooth phone) no multitasking capabilities worth mentioning and in general no e.g. weekly software updates, making the phone much more usable (even if it had to be done over USB, rather than over the network). I'm sure I was dumbfounded by the lack or design of other features as well, but they don't come to mind right now. To clarify, I'm not talking about smartphones here: my plain, 2-year old phone has a CPU an order of magnitude faster than my first PC, about as much storage space and it's ridiculous how bad (slow, unwieldy) the software is and it's not one phone or one manufacturer. What keeps the (to me) obvious software functionality vacuum on a capable hardware platform from being filled up? Edit: I believe a clarification on the multitasking point might be beneficial. I'll use my phone as an example, although the point is much more general. The phone can multitask and in fact does: you can listen to music and do something else at the same time. On the other hand, the way the software has been designed makes multitasking next to useless. (Ditto with the external touch screen: it can take touch commands, but only one application makes use of it, and only with 3 commands.) To take the multitasking example to the extreme, if I plug my phone into my laptop and it registers as an external disk, it doesn't allow any kind of operation: messages, calling, calendar, everything out of reach, although I can receive a call. No "battery life" issue there: it's charging while connected. BTW, another example of design below the current state of the art: I don't see a phone on the horizon which will remember where in an audio or video file you were when you stopped listening/watching it last time (podcasts are a good use case). Simplistic rewind/fast forward functionality only aggravates the problem.

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  • Accidental Complexity in OpenSSL HMAC functions

    - by Hassan Syed
    SSL Documentation Analaysis This question is pertaining the usage of the HMAC routines in OpenSSL. Since Openssl documentation is a tad on the weak side in certain areas, profiling has revealed that using the: unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d, int n, unsigned char *md, unsigned int *md_len); From here, shows 40% of my library runtime is devoted to creating and taking down **HMAC_CTX's behind the scenes. There are also two additional function to create and destroy a HMAC_CTX explicetly: HMAC_CTX_init() initialises a HMAC_CTX before first use. It must be called. HMAC_CTX_cleanup() erases the key and other data from the HMAC_CTX and releases any associated resources. It must be called when an HMAC_CTX is no longer required. These two function calls are prefixed with: The following functions may be used if the message is not completely stored in memory My data fits entirely in memory, so I choose the HMAC function -- the one whose signature is shown above. The context, as described by the man page, is made use of by using the following two functions: HMAC_Update() can be called repeatedly with chunks of the message to be authenticated (len bytes at data). HMAC_Final() places the message authentication code in md, which must have space for the hash function output. The Scope of the Application My application generates a authentic (HMAC, which is also used a nonce), CBC-BF encrypted protocol buffer string. The code will be interfaced with various web-servers and frameworks Windows / Linux as OS, nginx, Apache and IIS as webservers and Python / .NET and C++ web-server filters. The description above should clarify that the library needs to be thread safe, and potentially have resumeable processing state -- i.e., lightweight threads sharing a OS thread (which might leave thread local memory out of the picture). The Question How do I get rid of the 40% overhead on each invocation in a (1) thread-safe / (2) resume-able state way ? (2) is optional since I have all of the source-data present in one go, and can make sure a digest is created in place without relinquishing control of the thread mid-digest-creation. So, (1) can probably be done using thread local memory -- but how do I resuse the CTX's ? does the HMAC_final() call make the CTX reusable ?. (2) optional: in this case I would have to create a pool of CTX's. (3) how does the HMAC function do this ? does it create a CTX in the scope of the function call and destroy it ? Psuedocode and commentary will be useful.

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  • How to implement Xml Serialization with inherited classes in C#

    - by liorafar
    I have two classes : base class name Component and inheritd class named DBComponent [Serializable] public class Component { private string name = string.Empty; private string description = string.Empty; } [Serializable] public class DBComponent : Component { private List<string> spFiles = new List<string>(); // Storage Procedure Files [XmlArrayItem("SPFile", typeof(string))] [XmlArray("SPFiles")] public List<string> SPFiles { get { return spFiles; } set { spFiles = value; } } public DBComponent(string name, string description) : base(name, description) { } } [Serializable] public class ComponentsCollection { private static ComponentsCollection instance = null; private List<Component> components = new List<Component>(); public List<Component> Components { get { return components; } set { components = value; } } public static ComponentsCollection GetInstance() { if (ccuInstance == null) { lock (lockObject) { if (instance == null) PopulateComponents(); } } return instance; } private static void PopulateComponents() { instance = new CCUniverse(); XmlSerializer xs = new XmlSerializer(instance.GetType()); instance = xs.Deserialize(XmlReader.Create("Components.xml")) as ComponentsCollection; } } } I want read\write from a Xml file. I know that I need to implement the Serialization for DBComponent class otherwise it will not read it.But i cannot find any simple article for that. all the articles that I found were too complex for this simple scenario. The Xml file looks like this: <?xml version="1.0" encoding="utf-8" ?> <ComponentsCollection> <Components> <DBComponent Name="Tenant Historical Database" Description="Tenant Historical Database"> <SPFiles> <SPFile>Setup\TenantHistoricalSP.sql</SPFile> </SPFiles> </DBComponent> <Component Name="Agent" Description="Desktop Agent" /> </Components> </ComponentsCollection> Can someone please give me a simple example of how to read this kind of xml file and what should be implemented ? Thanks Lior

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  • Inference engine to calculate matching set according to internal rules

    - by Zecrates
    I have a set of objects with attributes and a bunch of rules that, when applied to the set of objects, provides a subset of those objects. To make this easier to understand I'll provide a concrete example. My objects are persons and each has three attributes: country of origin, gender and age group (all attributes are discrete). I have a bunch of rules, like "all males from the US", which correspond with subsets of this larger set of objects. I'm looking for either an existing Java "inference engine" or something similar, which will be able to map from the rules to a subset of persons, or advice on how to go about creating my own. I have read up on rule engines, but that term seems to be exclusively used for expert systems that externalize the business rules, and usually doesn't include any advanced form of inferencing. Here are some examples of the more complex scenarios I have to deal with: I need the conjunction of rules. So when presented with both "include all males" and "exclude all US persons in the 10 - 20 age group," I'm only interested in the males outside of the US, and the males within the US that are outside the 10 - 20 age group. Rules may have different priorities (explicitly defined). So a rule saying "exclude all males" will override a rule saying "include all US males." Rules may be conflicting. So I could have both an "include all males" and an "exclude all males" in which case the priorities will have to settle the issue. Rules are symmetric. So "include all males" is equivalent to "exclude all females." Rules (or rather subsets) may have meta rules (explicitly defined) associated with them. These meta rules will have to be applied in any case that the original rule is applied, or if the subset is reached via inferencing. So if a meta rule of "exclude the US" is attached to the rule "include all males", and I provide the engine with the rule "exclude all females," it should be able to inference that the "exclude all females" subset is equivalent to the "include all males" subset and as such apply the "exclude the US" rule additionally. I can in all likelihood live without item 5, but I do need all the other properties mentioned. Both my rules and objects are stored in a database and may be updated at any stage, so I'd need to instantiate the 'inference engine' when needed and destroy it afterward.

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  • How to communicate between Client and Server in a Client-Server Application?

    - by Sanoj
    I would like to implement an Client-Server Application, where the business-logic, security validations and a database are at the server and the user interface are at the client. I would like to implement clients in different languages i.e. one in WPF/.NET, one Swing/Java , one in Android/Java and maybe one HTML/JavaScript client. The server will be on Internet, so I would like to be able to have encrypted communication. The client will send some lists of items to be added to the database, or update items, and do some transactions. The server will check if the items are already updated by another client, or update the item, add new items or delete items. How do I solve the communication between clients and the server in such a system? I have been thinking about: http/https webserver, and sending messages in JSON or XML and use Web Sockets for bi-directional communication. Use http in a RESTful way, except when WebSockets are needed. But I guess there are better solutions for native desktop applications than http? CORBA - I have just heard about it, and it's old and complex. Not much talk about it these days. XMPP/Jabber - I have just heard about it and I don't know if it fits me at all. EJabberd seams to be a popular implementation. AMQP - I have just heard about it and I don't know if it fits me at all. RabbitMQ seams to be a popular implementation. Windows Communication Foundation, Java RMI, Java Message Service - but are they language independent? I guess some of these alternatives are on different levels, maybe I can have i.e xmpp or amqp in web sockets over https? What technologys are used for this problem in companies today? and what is recommended to use? I have no experience of them other than webservers and http. Please give me some guidance in this jungle. What are the pros and cons of these technologies in my situation?

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  • A continued saga of C# interoprability with unmanaged C++

    - by Gilad
    After a day of banging my head against the wall both literally and metaphorically, I plead for help: I have an unmanaged C++ project, which is compiled as a DLL. Let's call it CPP Project. It currently works in an unmanaged environment. In addition, I have created a WPF project, that shall be called WPF Project. This project is a simple and currently almost empty project. It contains a single window and I want it to use code from Project 1. For that, I have created a CLR C++ project, which shall be called Interop Project and is also compiled as a DLL. For simplicity I will attach some basic testing code I have boiled down to the basics. CPP Project has the following two testing files: tester.h #pragma once extern "C" class __declspec(dllexport) NativeTester { public: void NativeTest(); }; tester.cpp #include "tester.h" void NativeTester::NativeTest() { int i = 0; } Interop Project has the following file: InteropLib.h #pragma once #include <tester.h> using namespace System; namespace InteropLib { public ref class InteropProject { public: static void Test() { NativeTester nativeTester; nativeTester.NativeTest(); } }; } Lastly, WPF Project has a single window refrencing Interop Project: MainWindow.xaml.cs using System; using System.Windows; using InteropLib; namespace AppGUI { public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); InteropProject.Test(); } } } And the XAML itself has an empty window (default created). Once I am trying to run the WPF project, I get the following error: System.Windows.Markup.XamlParseException: 'The invocation of the constructor on type 'AppGUI.MainWindow' that matches the specified binding constraints threw an exception.' Line number '3' and line position '9'. --- System.IO.FileNotFoundException: Could not load file or assembly 'InteropLib.dll' or one of its dependencies. The specified module could not be found. at AppGUI.MainWindow..ctor() Interestingly enough, if I do not export the class from CPP Project, I do not get this error. Say, if i change tester.h to: #pragma once class NativeTester { public: void NativeTest() { int i = 0; } }; However, in this case I cannot use my more complex classes. If I move my implementation to a cpp file like before, I get unresolved linkage errors due to my not exporting my code. The C++ code I want to actually use is large and has many classes and is object oriented, so I can't just move all my implementation to the h files. Please help me understand this horrific error I've been trying resolve without success. Thanks.

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  • jcuda library usage problem

    - by user513164
    hi m very new to java and Linux i have a code which is taken from examples of jcuda.the code is following import jcuda.CUDA; import jcuda.driver.CUdevprop; import jcuda.driver.types.CUdevice; public class EnumDevices { public static void main(String args[]) { //Init CUDA Driver CUDA cuda = new CUDA(true); int count = cuda.getDeviceCount(); System.out.println("Total number of devices: " + count); for (int i = 0; i < count; i++) { CUdevice dev = cuda.getDevice(i); String name = cuda.getDeviceName(dev); System.out.println("Name: " + name); int version[] = cuda.getDeviceComputeCapability(dev); System.out.println("Version: " + String.format("%d.%d", version[0], version[1])); CUdevprop prop = cuda.getDeviceProperties(dev); System.out.println("Clock rate: " + prop.clockRate + " MHz"); System.out.println("Threads per block: " + prop.maxThreadsPerBlock); } } } I'm using Ubuntu as my operating system i compiled it with following command 1:-javac -cp /home/manish.yadav/Desktop/JCuda-All-0.3.2-bin-linux-x86_64 EnumDevices i got following error error: Class names, 'EnumDevices', are only accepted if annotation processing is explicitly requested 1 error i don't know what is the meaning of this error.what should i do to compile the program than i changed the compiling option which is javac -cp /home/manish.yadav/Desktop/JCuda-All-0.3.2-bin-linux-x86_64 EnumDevices.java than i got following error EnumDevices.java:36: clockRate is not public in jcuda.driver.CUdevprop; cannot be accessed from outside package System.out.println("Clock rate: " + prop.clockRate + " MHz"); ^ EnumDevices.java:37: maxThreadsPerBlock is not public in jcuda.driver.CUdevprop; cannot be accessed from outside package System.out.println("Threads per block: " + prop.maxThreadsPerBlock); ^ 2 errors Now I'm completely confused i don't know what to do? how to compile this program ? how to install the jcuda package or how to use it ? how to use package which have only jar files and .so files and the jar files don't having manifest file ? please help me

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  • Replace HTML entities in a string avoiding <img> tags

    - by Xeos
    I have the following input: Hi! How are you? <script>//NOT EVIL!</script> Wassup? :P LOOOL!!! :D :D :D Which is then run through emoticon library and it become this: Hi! How are you? <script>//NOT EVIL!</script> Wassup? <img class="smiley" alt="" title="tongue, :P" src="ui/emoticons/15.gif"> LOOOL!!! <img class="smiley" alt="" title="big grin, :D" src="ui/emoticons/5.gif"> <img class="smiley" alt="" title="big grin, :P" src="ui/emoticons/5.gif"> <img class="smiley" alt="" title="big grin, :P" src="ui/emoticons/5.gif"> I have a function that escapes HTML entites to prevent XSS. So running it on raw input for the first line would produce: Hi! How are you? &lt;script&gt;//NOT EVIL!&lt;/script&gt; Now I need to escape all the input, but at the same time I need to preserve emoticons in their initial state. So when there is <:-P emoticon, it stays like that and does not become &lt;:-P. I was thinking of running a regex split on the emotified text. Then processing each part on its own and then concatenating the string together, but I am not sure how easily can Regex be bypassed? I know the format will always be this: [<img class="smiley" alt="] [empty string] [" title="] [one of the values from a big list] [, ] [another value from the list (may be matching original emoticon)] [" src="ui/emoticons/] [integer from Y to X] [.gif">] Using the list MAY be slow, since I need to run that regex on text that may have 20-30-40 emoticons. Plus there may be 5-10-15 text messages to process. What could be an elegant solution to this? I am ready to use third-party library or jQuery for this. PHP preprocessing is possible as well.

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  • Prevent SQL Injection in Dynamic column names

    - by Mr Shoubs
    I can't get away without writing some dynamic sql conditions in a part of my system (using Postgres). My question is how best to avoid SQL Injection with the method I am currently using. EDIT (Reasoning): There are many of columns in a number of tables (a number which grows (only) and is maintained elsewhere). I need a method of allowing the user to decide which (predefined) column they want to query (and if necessary apply string functions to). The query itself is far too complex for the user to write themselves, nor do they have access to the db. There are 1000's of users with varying requirements and I need to remain as flexible as possible - I shouldn't have to revisit the code unless the main query needs to change - Also, there is no way of knowing what conditions the user will need to use. I have objects (received via web service) that generates a condition (the generation method is below - it isn't perfect yet) for some large sql queries. The _FieldName is user editable (parameter name was, but it didn't need to be) and I am worried it could be an attack vector. I put double quotes (see quoted identifier) around the field name in an attempt to sanitize the string, this way it can never be a key word. I could also look up the field name against a list of fields, but it would be difficult to maintain on a timely basis. Unfortunately the user must enter the condition criteria, I am sure there must be more I can add to the sanatize method? and does quoting the column name make it safe? (my limited testing seems to think so). an example built condition would be "AND upper(brandloaded.make) like 'O%' and upper(brandloaded.make) not like 'OTHERBRAND'" ... Any help or suggestions are appreciated. Public Function GetCondition() As String Dim sb As New Text.StringBuilder 'put quote around the table name in an attempt to prevent some sql injection 'http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html sb.AppendFormat(" {0} ""{1}"" ", _LogicOperator.ToString, _FieldName) Select Case _ConditionOperator Case ConditionOperatorOptions.Equals sb.Append(" = ") ... End Select sb.AppendFormat(" {0} ", Me.UniqueParameterName) 'for parameter Return Me.Sanitize(sb) End Function Private Function Sanitize(ByVal sb As Text.StringBuilder) As String 'compare against a similar blacklist mentioned here: http://forums.asp.net/t/1254125.aspx sb.Replace(";", "") sb.Replace("'", "") sb.Replace("\", "") sb.Replace(Chr(8), "") Return sb.ToString End Function Public ReadOnly Property UniqueParameterName() As String Get Return String.Concat(":" _UniqueIdentifier) End Get End Property

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  • chaining array of tasks with continuation

    - by Andrei Cristof
    I have a Task structure that is a little bit complex(for me at least). The structure is: (where T = Task) T1, T2, T3... Tn. There's an array (a list of files), and the T's represent tasks created for each file. Each T has always two subtasks that it must complete or fail: Tn.1, Tn.2 - download and install. For each download (Tn.1) there are always two subtasks to try, download from two paths(Tn.1.1, Tn.1.2). Execution would be: First, download file: Tn1.1. If Tn.1.1 fails, then Tn.1.2 executes. If either from download tasks returns OK - execute Tn.2. If Tn.2 executed or failed - go to next Tn. I figured the first thing to do, was to write all this structure with jagged arrays: private void CreateTasks() { //main array Task<int>[][][] mainTask = new Task<int>[_queuedApps.Count][][]; for (int i = 0; i < mainTask.Length; i++) { Task<int>[][] arr = GenerateOperationTasks(); mainTask[i] = arr; } } private Task<int>[][] GenerateOperationTasks() { //two download tasks Task<int>[] downloadTasks = new Task<int>[2]; downloadTasks[0] = new Task<int>(() => { return 0; }); downloadTasks[1] = new Task<int>(() => { return 0; }); //one installation task Task<int>[] installTask = new Task<int>[1] { new Task<int>(() => { return 0; }) }; //operations Task is jagged - keeps tasks above Task<int>[][] operationTasks = new Task<int>[2][]; operationTasks[0] = downloadTasks; operationTasks[1] = installTask; return operationTasks; } So now I got my mainTask array of tasks, containing nicely ordered tasks just as described above. However after reading the docs on ContinuationTasks, I realise this does not help me since I must call e.g. Task.ContinueWith(Task2). I'm stumped about doing this on my mainTask array. I can't write mainTask[0].ContinueWith(mainTask[1]) because I dont know the size of the array. If I could somehow reference the next task in the array (but without knowing its index), but cant figure out how. Any ideas? Thank you very much for your help. Regards,

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  • c++ exceptions and program execution logic

    - by Andrew
    Hello everyone, I have been thru a few questions but did not find an answer. I wonder how should the exception handling be implemented in a C++ software so it is centralized and it is tracking the software progress? For example, I want to process exceptions at four stages of the program and know that exception happened at that specific stage: 1. Initialization 2. Script processing 3. Computation 4. Wrap-up. At this point, I tried this: int main (...) { ... // start logging system try { ... } catch (exception &e) { cerr << "Error: " << e.what() << endl; cerr << "Could not start the logging system. Application terminated!\n"; return -1; } catch(...) { cerr << "Unknown error occured.\n"; cerr << "Could not start the logging system. Application terminated!\n"; return -2; } // open script file and acquire data try { ... } catch (exception &e) { cerr << "Error: " << e.what() << endl; cerr << "Could not acquire input parameters. Application terminated!\n"; return -1; } catch(...) { cerr << "Unknown error occured.\n"; cerr << "Could not acquire input parameters. Application terminated!\n"; return -2; } // computation try { ... } ... This is definitely not centralized and seems stupid. Or maybe it is not a good concept at all?

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  • Closure Tables - Is this enough data to display a tree view?

    - by James Pitt
    Here is the table I have created by testing the closure table method. | id | parentId | childId | hops | | | | | 270 | 6 | 6 | 0 | 271 | 7 | 7 | 0 | 272 | 8 | 8 | 0 | 273 | 9 | 9 | 0 | 276 | 10 | 10 | 0 | 281 | 9 | 10 | 1 | 282 | 7 | 9 | 1 | 283 | 7 | 10 | 2 | 285 | 7 | 8 | 1 | 286 | 6 | 7 | 1 | 287 | 6 | 9 | 2 | 288 | 6 | 10 | 3 | 289 | 6 | 8 | 2 | 293 | 6 | 9 | 1 | 294 | 6 | 10 | 2 I am trying to create a simple tree of this using PHP. There does not seem to be enough data to create the table. For example, when I look purely at parentId = 6: -Part 6 -Part 7 - ? - ? -Part 9 - ? - ? We know that parts 8 and 10 exists below Part 7 or 9, but not which. We know that part 10 exists at both 3 and 4 nodes deep but where? If I look at other data in the table it is possible to tell it should be: - Part 6 - Part 7 - Part 9 - Part 10 - Part 9 - Part 10 I thought one of the benefits of closure tables was there was no need for recursive queries? Could you help explain what I am doing wrong? EDIT: For clarification, this is a mapping table. There is another table called "parts" which has a column called part_id that correlates to both the parentId and childId columns in the "closure" table. The "id" column in the table above (closure) is just for the purposes of maintaining a primary key. It is not really necessary. The methods I have used to create this closure table is described in the following article: http://dirtsimple.org/2010/11/simplest-way-to-do-tree-based-queries.html EDIT2: It can have two and three hops. I will explain easier by assigning names to the items. Part 6 = Bicycle Part 7 = Gears Part 8 = Chain Part 9 = Bolt Part 10 = Nut Nut is part of Bolt. The Bolt and Nut combo exists directly within Bicycle and within Gears which is part of Bicycle. In relation to what method to use I have looked at Adjacency, Edges, Enum Paths, Closures, DAGS(networks) and the Nested Set Model. I am still trying to work out what is what, but this is an extremely complex component database where there are multiple parents and any modification to a sub-tree must propogate through the other trees. More importantly there will be insertions, deletions and tree views that I wish to avoid recursion during general use, even at the cost of database space and query time during entry.

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  • Is READ UNCOMMITTED / NOLOCK safe in this situation?

    - by Ben Challenor
    I know that snapshot isolation would fix this problem, but I'm wondering if NOLOCK is safe in this specific case so that I can avoid the overhead. I have a table that looks something like this: drop table Data create table Data ( Id BIGINT NOT NULL, Date BIGINT NOT NULL, Value BIGINT, constraint Cx primary key (Date, Id) ) create nonclustered index Ix on Data (Id, Date) There are no updates to the table, ever. Deletes can occur but they should never contend with the SELECT because they affect the other, older end of the table. Inserts are regular and page splits to the (Id, Date) index are extremely common. I have a deadlock situation between a standard INSERT and a SELECT that looks like this: select top 1 Date, Value from Data where Id = @p0 order by Date desc because the INSERT acquires a lock on Cx (Date, Id; Value) and then Ix (Id, Date), but the SELECT acquires a lock on Ix (Id, Date) and then Cx (Date, Id; Value). This is because the SELECT first seeks on Ix and then joins to a seek on Cx. Swapping the clustered and non-clustered index would break this cycle, but it is not an acceptable solution because it would introduce cycles with other (more complex) SELECTs. If I add NOLOCK to the SELECT, can it go wrong in this case? Can it return: More than one row, even though I asked for TOP 1? No rows, even though one exists and has been committed? Worst of all, a row that doesn't satisfy the WHERE clause? I've done a lot of reading about this online, but the only reproductions of over- or under-count anomalies I've seen (one, two) involve a scan. This involves only seeks. Jeff Atwood has a post about using NOLOCK that generated a good discussion. I was particularly interested in a comment by Rick Townsend: Secondly, if you read dirty data, the risk you run is of reading the entirely wrong row. For example, if your select reads an index to find your row, then the update changes the location of the rows (e.g.: due to a page split or an update to the clustered index), when your select goes to read the actual data row, it's either no longer there, or a different row altogether! Is this possible with inserts only, and no updates? If so, then I guess even my seeks on an insert-only table could be dangerous. Update: I'm trying to figure out how snapshot isolation works. It seems to be row-based, where transactions read the table (with no shared lock!), find the row they are interested in, and then see if they need to get an old version of the row from the version store in tempdb. But in my case, no row will have more than one version, so the version store seems rather pointless. And if the row was found with no shared lock, how is it different to just using NOLOCK?

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  • Algorithm for finding symmetries of a tree

    - by Paxinum
    I have n sectors, enumerated 0 to n-1 counterclockwise. The boundaries between these sectors are infinite branches (n of them). The sectors live in the complex plane, and for n even, sector 0 and n/2 are bisected by the real axis, and the sectors are evenly spaced. These branches meet at certain points, called junctions. Each junction is adjacent to a subset of the sectors (at least 3 of them). Specifying the junctions, (in pre-fix order, lets say, starting from junction adjacent to sector 0 and 1), and the distance between the junctions, uniquely describes the tree. Now, given such a representation, how can I see if it is symmetric wrt the real axis? For example, n=6, the tree (0,1,5)(1,2,4,5)(2,3,4) have three junctions on the real line, so it is symmetric wrt the real axis. If the distances between (015) and (1245) is equal to distance from (1245) to (234), this is also symmetric wrt the imaginary axis. The tree (0,1,5)(1,2,5)(2,4,5)(2,3,4) have 4 junctions, and this is never symmetric wrt either imaginary or real axis, but it has 180 degrees rotation symmetry if the distance between the first two and the last two junctions in the representation are equal. Edit: This is actually for my research. I have posted the question at mathoverflow as well, but my days in competition programming tells me that this is more like an IOI task. Code in mathematica would be excellent, but java, python, or any other language readable by a human suffices. Here are some examples (pretend the double edges are single and we have a tree) http://www2.math.su.se/~per/files.php?file=contr_ex_1.pdf http://www2.math.su.se/~per/files.php?file=contr_ex_2.pdf http://www2.math.su.se/~per/files.php?file=contr_ex_5.pdf Example 1 is described as (0,1,4)(1,2,4)(2,3,4)(0,4,5) with distances (2,1,3). Example 2 is described as (0,1,4)(1,2,4)(2,3,4)(0,4,5) with distances (2,1,1). Example 5 is described as (0,1,4,5)(1,2,3,4) with distances (2). So, given the description/representation, I want to find some algorithm to decide if it is symmetric wrt real, imaginary, and rotation 180 degrees. The last example have 180 degree symmetry. (These symmetries corresponds to special kinds of potential in the Schroedinger equation, which has nice properties in quantum mechanics.)

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  • XML validation in Java - why does this fail?

    - by jd
    hi, first time dealing with xml, so please be patient. the code below is probably evil in a million ways (I'd be very happy to hear about all of them), but the main problem is of course that it doesn't work :-) public class Test { private static final String JSDL_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl"; private static final String JSDL_POSIX_APPLICATION_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl-posix"; public static void main(String[] args) { System.out.println(Test.createJSDLDescription("/bin/echo", "hello world")); } private static String createJSDLDescription(String execName, String args) { Document jsdlJobDefinitionDocument = getJSDLJobDefinitionDocument(); String xmlString = null; // create the elements Element jobDescription = jsdlJobDefinitionDocument.createElement("JobDescription"); Element application = jsdlJobDefinitionDocument.createElement("Application"); Element posixApplication = jsdlJobDefinitionDocument.createElementNS(JSDL_POSIX_APPLICATION_SCHEMA_URL, "POSIXApplication"); Element executable = jsdlJobDefinitionDocument.createElement("Executable"); executable.setTextContent(execName); Element argument = jsdlJobDefinitionDocument.createElement("Argument"); argument.setTextContent(args); //join them into a tree posixApplication.appendChild(executable); posixApplication.appendChild(argument); application.appendChild(posixApplication); jobDescription.appendChild(application); jsdlJobDefinitionDocument.getDocumentElement().appendChild(jobDescription); DOMSource source = new DOMSource(jsdlJobDefinitionDocument); validateXML(source); try { Transformer transformer = TransformerFactory.newInstance().newTransformer(); transformer.setOutputProperty(OutputKeys.INDENT, "yes"); StreamResult result = new StreamResult(new StringWriter()); transformer.transform(source, result); xmlString = result.getWriter().toString(); } catch (Exception e) { e.printStackTrace(); } return xmlString; } private static Document getJSDLJobDefinitionDocument() { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = null; try { builder = factory.newDocumentBuilder(); } catch (Exception e) { e.printStackTrace(); } DOMImplementation domImpl = builder.getDOMImplementation(); Document theDocument = domImpl.createDocument(JSDL_SCHEMA_URL, "JobDefinition", null); return theDocument; } private static void validateXML(DOMSource source) { try { URL schemaFile = new URL(JSDL_SCHEMA_URL); Sche maFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); Schema schema = schemaFactory.newSchema(schemaFile); Validator validator = schema.newValidator(); DOMResult result = new DOMResult(); validator.validate(source, result); System.out.println("is valid"); } catch (Exception e) { e.printStackTrace(); } } } it spits out a somewhat odd message: org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'JobDescription'. One of '{"http://schemas.ggf.org/jsdl/2005/11/jsdl":JobDescription}' is expected. Where am I going wrong here? Thanks a lot

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  • Non Document Centric SharePoint Workflow

    - by Dan Revell
    SharePoint workflows are document centric in that the base thing the workflow runs on has to be a thing; be it a document or just a list item. The workflow itself is task based, so stuff a user has to do. Now I can put any sort of code in these tasks that I want to and even put complex InfoPath forms in for the user to perform the task. This has been fine on all my previous workflows. But what if I want the tasks to be actual official forms themselves. The item that the workflow runs on is just some abstract concept like an event. An example could be an accident has happened. There isn't an accident form, but a whole set of forms that need to be completed by different people. Task forms aren't really a nice way to go, because it locks all the forms into the task list. You can only access the forms by not deleting the tasks when complete and going to the workflow summery and following the task links to the InfoPath forms or going straight to the tasks list and doing a filter on particular "accidents". These are official documents so ideally there would be a library for each type of document and the workflow would orchestrate the completion of the right forms. It would mean each task would have to create a new blank form and then link the user to that form. The user would go complete the form but then have to go back to the task form and click yes I've completed it until the workflow could progress. Well this is short of the workflow monitoring the forms library form for some completion trigger. But then it all gets messy with the user experience from clicking the link in the task email, to open the Infopath task form, to clicking the link in the subsequent Infopath library form and then return through these forms on completion. It just gets messy trying to retrofit this non document centric sort of workflow into SharePoint. I would really appreciate any input on what might be the best way to do this. Store the forms as task forms Store the forms as library forms and create/link from the task forms Store the forms as different infopath views, and use a forms library. The workflow would trigger variables that progress the view the infopath form shows. Using the same form template for both task forms and a forms library and when a task form is complete, copy the xml into the forms library to have a official record outside of the workflow. Thanks

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  • response.redirect to classic asp failing {Unable to evaluate expression because the code is optimize

    - by jeff
    I have the following code pasted below. For some reason, the response.redirect seems to be failing and it is maxing out the cpu on my server and just doesn't do anything. The .net code uploads the file fine, but does not redirect to the asp page to do the processing. I know this is absolute rubbish why would you have .net code redirecting to classic asp, it is a legacy app. I have tried putting false or true etc. at the end of the redirect as I have read other people have had issues with this. Please help as it's driving me insane! It's so strange, it runs locally on my machine but won't run on my server! I am getting the following error when I debugged remotely. {Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack.} (UPDATED) After debugging remotely and taking the redirect out of the try catch, I have found that the redirect is trying to get to the correct location but after it leaves the redirect is just seems to get lost. (almost as if it can't navigate away from the cobra_import project) back up a level to COBRA/pages. Why is this??? This has worked previously!!! public void btnUploadTheFile_Click(object Source, EventArgs evArgs) { //need to check that the uploaded file is an xls file. string strFileNameOnServer = "PJI3.txt"; string strBaseLocation = ConfigurationSettings.AppSettings["str_file_location"]; if ("" == strFileNameOnServer) { txtOutput.InnerHtml = "Error - a file name must be specified."; return; } if (null != uplTheFile.PostedFile) { try { uplTheFile.PostedFile.SaveAs(strBaseLocation+strFileNameOnServer); txtOutput.InnerHtml = "File <b>" + strBaseLocation+strFileNameOnServer+"</b> uploaded successfully"; Response.Redirect ("/COBRA/pages/sap_import_pji3_prc.asp"); } catch (Exception e) { txtOutput.InnerHtml = "Error saving <b>" + strBaseLocation+strFileNameOnServer+"</b><br>"+ e.ToString(); } } }

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  • Dynamic data-entry value store

    - by simendsjo
    I'm creating a data-entry application where users are allowed to create the entry schema. My first version of this just created a single table per entry schema with each entry spanning a single or multiple columns (for complex types) with the appropriate data type. This allowed for "fast" querying (on small datasets as I didn't index all columns) and simple synchronization where the data-entry was distributed on several databases. I'm not quite happy with this solution though; the only positive thing is the simplicity... I can only store a fixed number of columns. I need to create indexes on all columns. I need to recreate the table on schema changes. Some of my key design criterias are: Very fast querying (Using a simple domain specific query language) Writes doesn't have to be fast Many concurrent users Schemas will change often Schemas might contain many thousand columns The data-entries might be distributed and needs syncronization. Preferable MySQL and SQLite - Databases like DB2 and Oracle is out of the question. Using .Net/Mono I've been thinking of a couple of possible designs, but none of them seems like a good choice. Solution 1: Union like table containing a Type column and one nullable column per type. This avoids joins, but will definitly use a lot of space. Solution 2: Key/value store. All values are stored as string and converted when needed. Also use a lot of space, and of course, I hate having to convert everything to string. Solution 3: Use an xml database or store values as xml. Without any experience I would think this is quite slow (at least for the relational model unless there is some very good xpath support). I also would like to avoid an xml database as other parts of the application fits better as a relational model, and being able to join the data is helpful. I cannot help to think that someone has solved (some of) this already, but I'm unable to find anything. Not quite sure what to search for either... I know market research is doing something like this for their questionnaires, but there are few open source implementations, and the ones I've found doesn't quite fit the bill. PSPP has much of the logic I'm thinking of; primitive column types, many columns, many rows, fast querying and merging. Too bad it doesn't work against a database.. And of course... I don't need 99% of the provided functionality, but a lot of stuff not included. I'm not sure this is the right place to ask such a design related question, but I hope someone here has some tips, know of any existing work, or can point me to a better place to ask such a question. Thanks in advance!

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  • Excel string manipulation to check data consistency

    - by chefsmart
    Background information: - There are nearly 7000 individuals and there is data about their performances in one, two or three tests. Every individual has taken the 1st test (let's call it Test M). Some of those who have taken Test M have also taken Test I, and some of those who have taken Test I have also taken Test B. For the first two tests (M and I), students can score grades I, II, or III. Depending on the grades they are awarded points -- 3 for grade I, 2 for II, 1 for III. The last Test B is just a pass or a fail result with no grades. Those passing this test get 1 point, with no points for failure. (Well actually, grades are awarded, but all grades are given a common 1 point). An amateur has entered data to represent these students and their grades in an Excel file. Problem is, this person has done the worst thing possible - he has developed his own notation and entered all test information in a single cell --- and made my life hell. The file originally had two text columns, one for individual's id, and the second for test info, if one could call it that. It's horrible, I know, and I am suffering. In the image, if you see "M-II-2 I-III-1" it means the person got grade II in Test M for 2 points and grade III in Test I for 1 point. Some have taken only one test, some two, and some three. When the file came to me for processing and analyzing the performance of students, I sent it back with instructions to insert 3 additional columns with only the grades for the three tests. The file now looks as follows. Columns C and D represent grades I, II, and III using 1,2 and 3 respectively. Column C is for Test M, column D for Test I. Column E says BA (B Achieved!) if the individual has passed Test B. Now that you have the above information, let's get to the problem. I don't trust this and want to check whether data in column B matches with data in columns C,D and E. That is, I want to examine the string in column B and find out whether the figures in columns C,D and E are correct. All help is really appreciated. P.S. - I had exported this to MySQL via ODBC and that is why you are seeing those NULLs. I tried doing this in MySQL too, and really will accept a MySQL or an Excel solution, I don't have a preference. Edit : - See file with sample data

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  • open,edit and save xml file with schema using php

    - by Neat
    Hy... I'm new in XML Schema, XSL,... (I have basic understanding) On web page: http://w3schools.com/xsl/xsl_editxml.asp is shown example for open,edit,save xml file, but with asp. Do anyone know how can i open/edit and save xml file using php for next example: <?xml version="1.0" encoding="ISO-8859-1"?> <tools> <tool id="1"> <field id="prodName"> <value>HAMMER HG2606</value> </field> <field id="prodNo"> <value>32456240</value> </field> <field id="price"> <value>$30.00</value> </field> </tool> <tool id="2"> <field id="prodName"> <value>Audi</value> </field> <field id="prodNo"> <value>88885</value> </field> <field id="price"> <value>$26.00</value> </field> </tool> </tools> and do i need <tool id="2"> or just <tool> is enough. Thanks very much on replay, and i don't need another xsl like shown on w3s, just fine is refresh submitted php file after submit (will do something with ajax after). I saw replay from Mr. Writman on questions/377632/add-update-and-edit-an-xml-file-with-php but that is for now 2 complex for me...:) is there any simpler answer (solution). Thanks in advance!!!

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  • A SelfHosted WCF Service over Basic HTTP Binding doesn't support more than 1000 concurrent requests

    - by Krishnan
    I have self hosted a WCF Service over BasicHttpBinding consumed by an ASMX Client. I'm simulating a concurrent user load of 1200 users. The service method takes a string parameter and returns a string. The data exchanged is less than 10KB. The processing time for a request is fixed at 2 seconds by having a Thread.Sleep(2000) statement. Nothing additional. I have removed all the DB Hits / business logic. The same piece of code runs fine for 1000 concurrent users. I get the following error when I bump up the number to 1200 users. System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) --- End of inner exception stack trace --- at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead) --- End of inner exception stack trace --- at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request) at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at WCF.Throttling.Client.Service.Function2(String param) This exception is often reported on DataContract mismatch and large data exchange. But never when doing a load test. I have browsed enough and have tried most of the options which include, Enabled Trace & Message log on server side. But no errors logged. To overcome Port Exhaustion MaxUserPort is set to 65535, and TcpTimedWaitDelay 30 secs. MaxConcurrent Calls is set to 600, and MaxConcurrentInstances is set to 1200. The Open, Close, Send and Receive Timeouts are set to 10 Minutes. The HTTPWebRequest KeepAlive set to false. I have not been able to nail down the issue for the past two days. Any help would be appreciated. Thank you.

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  • deleted gen folder, eclipse isn't generating it now :(

    - by LuxuryMode
    I accidentally deleted my gen folder and now, predictably, my resources are all messed up. I just created a gen folder myself and tried to project clean - that didn't work. Tried right-clicking project and going to android tools fix project properties - didn't work. Tried unchecking build automatically...didn't work. cleaned, closed project, closed eclipse, restarted, etc, etc. Nothing is working and I keep seeing this error: gen already exists but is not a source folder. Convert to a source folder or rename it. EDIT - OK was able to generate R.java, but now I'm getting crazy stuff in the console: [2011-06-14 17:06:11 - fastapp] Conversion to Dalvik format failed with error 1 [2011-06-14 17:06:42 - fastapp] Dx trouble processing "java/awt/font/NumericShaper.class": Ill-advised or mistaken usage of a core class (java.* or javax.*) when not building a core library. This is often due to inadvertently including a core library file in your application's project, when using an IDE (such as Eclipse). If you are sure you're not intentionally defining a core class, then this is the most likely explanation of what's going on. However, you might actually be trying to define a class in a core namespace, the source of which you may have taken, for example, from a non-Android virtual machine project. This will most assuredly not work. At a minimum, it jeopardizes the compatibility of your app with future versions of the platform. It is also often of questionable legality. If you really intend to build a core library -- which is only appropriate as part of creating a full virtual machine distribution, as opposed to compiling an application -- then use the "--core-library" option to suppress this error message. If you go ahead and use "--core-library" but are in fact building an application, then be forewarned that your application will still fail to build or run, at some point. Please be prepared for angry customers who find, for example, that your application ceases to function once they upgrade their operating system. You will be to blame for this problem. If you are legitimately using some code that happens to be in a core package, then the easiest safe alternative you have is to repackage that code. That is, move the classes in question into your own package namespace. This means that they will never be in conflict with core system classes. JarJar is a tool that may help you in this endeavor. If you find that you cannot do this, then that is an indication that the path you are on will ultimately lead to pain, suffering, grief, and lamentation. [2011-06-14 17:06:42 - fastapp] Dx 1 error; aborting [2011-06-14 17:06:42 - fastapp] Conversion to Dalvik format failed with error 1 And eclipse can't resolve the import of my resources import com.me.fastapp.R;

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  • Animation using AniMate with Unity3D doesn't interact with physical objects

    - by Albz
    I'm designing a maze with Unity3D. The maze has a number of bifurcations and the player will stop before each bifurcation and simply choose left or right. Then an automatic animation will move the player through the next bifurcation till the end of the maze (or till a dead end). To animate the player I'm using AniMate and C# in my Unity project. Using AniMate I'm simply creating a point-to-point animation for each bifurcation (e.g. mage below: from the start/red arrow to point 5) My problem is that my animation script (associated to the "First Person Controller") is not working properly since physics is not respected (the player passes through walls). If in the same project I enable the standard character controls in Unity, then I can navigate in the maze with the physical contrains of walls etc... (i.e. I have colliders). This is an example of the code I'm using when I press left to pass from starting point, trough point 1 to point 2: void FixedUpdate () { if (Input.GetKey(KeyCode.LeftArrow)) { //To point 1 Hashtable props = new Hashtable(); props.Add("position", new Vector3(756f,112f,1124f)); props.Add("physics", true); Ani.Mate.To(transform, 2, props); //To point 2 Hashtable props2 = new Hashtable(); props2.Add("position", new Vector3(731f,112f,1124f)); props2.Add("physics", true); Ani.Mate.To(transform, 2, props2); } } What happens practically when I press the left arrow button is that the player moves directly to point 2 using a straight line passing through the wall. I tried to pass to AniMate "Physics = true" but it doesn't seem to help. Any idea on how to solve this issue? Alternatively... any hint on how to have a more optimized code and just use a series of vector3 coordinates (one for each point) to obtain the simple animation I want without having to declare new Hashtable(); etc... every time? I chose AniMate simply because 1. I'm a beginner with Unity 2. I don't need complex animations (e.g. I don't need to use iTween), just fixed animations along straight lines and I need something really simple and quick to implement in a script. However, if someone has an equally simple solution it will be welcome. thank you in advance for your help

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  • LinqToXML why does my object go out of scope? Also should I be doing a group by?

    - by Kettenbach
    Hello All, I have an IEnumerable<someClass>. I need to transform it into XML. There is a property called 'ZoneId'. I need to write some XML based on this property, then I need some decendent elements that provide data relevant to the ZoneId. I know I need some type of grouping. Here's what I have attempted thus far without much success. **inventory is an IEnumerable<someClass>. So I query inventory for unique zones. This works ok. var zones = inventory.Select(c => new { ZoneID = c.ZoneId , ZoneName = c.ZoneName , Direction = c.Direction }).Distinct(); No I want to create xml based on zones and place. ***place is a property of 'someClass'. var xml = new XElement("MSG_StationInventoryList" , new XElement("StationInventory" , zones.Select(station => new XElement("station-id", station.ZoneID) , new XElement("station-name", station.ZoneName)))); This does not compile as "station" is out of scope when I try to add the "station-name" element. However is I remove the paren after 'ZoneId', station is in scope and I retreive the station-name. Only problem is the element is then a decendant of 'station-id'. This is not the desired output. They should be siblings. What am I doing wrong? Lastly after the "station-name" element, I will need another complex type which is a collection. Call it "places'. It will have child elements called "place". its data will come from the IEnumerable and I will only want "places" that have the "ZoneId" for the current zone. Can anyone point me in the right direction? Is it a mistake select distinct zones from the original IEnumerable? This object has all the data I need within it. I just need to make it heirarchical. Thanks for any pointers all. Cheers, Chris in San Diego

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  • What is the best way to read and write cXML documents in C# ?

    - by tetranz
    I know this is a vague open ended question. I'm hoping to get some general direction. I need to add cXML punchout to an ASP.NET C# site / application. This is replacing something that I wrote years ago in ColdFusion. I'm a reasonably experienced C# developer but I haven't done much with XML. There seems to be lots of different options for processing XML in .NET. Here's the open ended question: Assuming that I have an XML document in some form, eg a file or a string, what is the best way to read it into my code? I want to get the data and then query databases etc. The cXML document size and our traffic volumes are easily small enough so that loading the a cXML document into memory is not a problem. Should I: 1) Manually build classes based on the dtd and use the XML Serializer? 2) Use a tool to generate classes. There are sample cXML files downloadable from Ariba.com. I tried xsd.exe to generate an xsd and then xsd.exe /c to generate classes. When I try to deserialize I get errors because there seems to be "confusion" around whether some elements should be single values or arrays. I tried the CodeXS online tool but that gives errors in it's log and errors if I try to deserialize a sample document. 2) Create a dataset and ReadXml()? 3) Create a typed dataset and ReadXml()? 4) Use Linq to XML. I often use Linq to Objects so I'm familiar with Linq in general but I'm struggling to see what it gives me in this situation. 5) Some other means. I guess I need to improve my understanding of XML in general but even so ... am I missing some obvious way of doing this? In the old ColdFusion site I found a free component ("tag") which basically ignored any schema and read the XML into a "structure" which is essentially a series of nested hash tables which was then easy to read in code. That was probably quite sloppy but it worked. I also need to generate XML files from my C# objects. Maybe Linq to XML will be good for that. I could start with a default "template" document and manipulate it before saving. Thanks for any pointers ...

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